870 WEED FLORA OF IOWA 



Scabrous. Having a rough surface. 



Scale. Any thin appendage, morphologically a modified, degen- 

 erated leaf. 



Scape. A peduncle rising from the root, without proper foliage. 



Scapose. Resembling a scape. 



Scarious. Dry and membranous. 



Sclerenchyma. Lignified tissue as applied to thick-walled fibers. 



Sclerotic. Consisting of sclerenchyma. 



Seed. The ripened ovule, enclosing a rudimentary plant, and 

 the food necessary for its germination. 



Sepal. A division of the calyx. 



Serrate. Having sharp teeth pointing forward. 



Serrulate. Finely serrate. 



Sessile. Without a stalk ; thus a leaf is sessile when the blade is 

 seated directly upon the stem. 



Sheath. A tubular envelope as the sheath of grasses. 



Shrub. A woody perennial smaller than a tree and usually hav- 

 ing several stems. 



Simple. Without subdivisions, opposed to compound; leaves, as 

 oak, dock, etc. 



Sinuate. Having strongly wavy margin. 



Sinuous. Wavy, curving back and forth. 



Sinus. The cleft between two lobes or divisions. 



Spatulate. Shaped like a druggist's spatula, rounded at the 

 summit and gradually narrowed downward. 



Spicate. Arranged in a spike. 



Spike. An inflorescence like a raceme, except that the flowers are 

 sessile. 



Spikelet. The characteristic inflorescence of grasses. 



Spindle-shaped. See Fusiform. 



Spine. A sharp, rigid process growing from the stem. 



Sporangium. Spore case. 



Spore. Pollen grain ; reproductive body of flowerless plants. 



Spreading. Applied to branches that bend outward at less than 

 a right angle. 



Stamen. A pollen-bearing organ of a flower. 



Staminate. Applied to a flower or plant which has stamens, but 

 no pistils. 



Stellate. Star-shaped. 



Sterile. Unfruitful, as a flower without a pistil or antherless 

 stamen. 



